Date of this Version
Littlefield, C.D. Autumn sandhill crane migration in southeastern Oregon. In: Wood D. A., ed. 1992. Proceedings 1988 North American Crane Workshop, Feb. 22–24, 1988. Lake Wales, Florida (Tallahassee, FL: State of Florida Game and Fresh Water Fish Commission Nongame Wildlife Program Technical Report #12, 1992), pp. 47-54.
Each autumn, from 2,000 to 3,000 greater sandhill cranes (Grus canadensis tabida) of the Central Valley Population congregate on Malheur National Wildlife Refuge. Migratory behavIor, flock SIzes and arrivals and departures from this important autumn use area were observed for 13 years (1970-1986). Average size of flocks arriving from the north was 15.7, with those arriving from the southwest averaging 7.4. Flocks departing for California wintering areas averaged 9.2, but as smaller groups merged, flock , sizes increased to 24.8 (35 km southwest from the departure area). Most flIghts were at speeds ra~?mg from 56 to 88 kmh-l, at altitudes ranging from 150 to 900 m. If favorable habitat and weather condItions occurred in September and October, en masse migrations generally did not occur untII.November. Most southward departures occurred when winds aloft were from a northerly quadrat but wmd dIrection was less important for birds arriving onto the refuge.